06/17/2026
The next time you go to buy drain cleaner, be sure you know what you are buying and what type of piping you have. The pictures attached are an example of sulfuric acid which is used in many commercial type heavy duty drain cleaning chemicals. This pipe was made of cast iron and the pipe had a dip, or what we call a belly to it. When the acid was poured in, it would pool in the belly of the pipe and slowly eat the bottom of the pipe out.
Sulfuric acid will eat and attack anything that contains any metallic properties. This includes copper, brass (commonly found under sinks for the traps and tub drains), cast iron (which is very common in older homes and under basement floors as well as floor drains, and can even react with stainless steel.
Not only are sulfuric acid based drain cleaners harmful to pipes, they are also very dangerous to human body, causing skin burns, damaged to the eyes, and the fumes can become deadly if mixed with other types of drain cleaners.
More often than not, we find drain cleaners to be nothing more than a temporary solution to an issue that needs to be addressed further. While not all drain cleaners contain sulfuric acid, there are some that are safe for this piping. Please read the labels and be aware of what you are putting down your drain.
